Solar panels for vehicles

Abstract

The mounting area of ​​solar panels will be increased, thereby increasing the amount of electricity generated by the solar panels. [Solution] An in-vehicle solar panel comprising a plurality of solar cell modules arranged in a grid pattern on the surface of the solar cell panel, wherein the solar cell panel has a shape in which adjacent solar cell modules in at least one continuous arrangement direction are bent in an alternating mountain fold and valley fold pattern, each solar cell module has a plurality of strip-shaped solar cells electrically connected in series, and the plurality of solar cell modules are electrically connected in parallel to one another.

Description

Technical Field

[0001] The present disclosure relates to an in-vehicle solar panel.

Background Art

[0002] Vehicles with solar cells installed on the vehicle roof are known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a vehicle equipped with a solar panel, it is desired to increase the mounting area of the solar panel and the power generation amount. However, since it is necessary to mount the solar panel within a limited installation area such as the vehicle roof, the mounting area of the solar panel and the power generation amount by the solar panel have been limited.

Means for Solving the Problems

[0005] The present disclosure can be realized in the following forms.

[0006] (1) According to one embodiment of the present disclosure, a solar panel for use in a vehicle is provided. The solar panel comprises a plurality of solar cell modules arranged in a grid pattern that constitute the surface of the solar panel, the solar panel having a shape in which adjacent solar cell modules in at least one continuous arrangement direction are bent in alternating mountain and valley folds, each solar cell module has a plurality of strip-shaped solar cells electrically connected in series, and the plurality of solar cell modules are electrically connected in parallel to one another. With this embodiment of the solar panel, since the solar panel has a shape in which adjacent solar cell modules are bent in alternating mountain and valley folds, the mounting area of ​​the solar panel can be increased compared to a configuration in which the solar panel is arranged flat with respect to the mounting surface of the vehicle. As a result, the amount of power generated by the solar panel can be increased.

[0007] Furthermore, since multiple solar cell modules are electrically connected in parallel, even if the current value in one solar cell module is low, the overall decrease in the current value of the solar panel can be suppressed. This helps to suppress the decrease in power generation from the solar panel.

[0008] Furthermore, since each solar cell module has multiple strip-shaped solar cells electrically connected in series, the sum of the voltages across multiple solar cells can be used as the output voltage of each solar cell module, thereby increasing the output voltage of each solar cell module. This allows the power generated by the solar panel to be appropriately supplied to various devices. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic perspective view showing the solar cell panel in this embodiment. [Figure 2] This is a schematic cross-sectional view showing a portion of the solar cell panel in this embodiment. [Figure 3]This is an explanatory diagram illustrating the electrical connections of the solar panel in this embodiment. [Modes for carrying out the invention]

[0010] A. Embodiment A1. Overall configuration of solar panel 10: The overall configuration of the solar cell panel 10 in this embodiment will be explained using Figures 1 and 2. Figure 1 is a schematic perspective view showing the solar cell panel 10 in this embodiment. Figure 2 is a schematic cross-sectional view showing a part of the solar cell panel 10 in this embodiment. The x-axis, y-axis, and z-axis directions in Figures 1 to 3 are for convenience in explaining this embodiment. As shown in Figures 1 to 3, the directions in which the solar cell panel 10 extends are defined as the x-axis and y-axis directions, and the direction perpendicular to the direction in which the solar cell panel 10 extends is defined as the z-axis direction. The z-axis direction is also called the up and down direction, and the direction indicated by the z-axis arrow is called the up direction.

[0011] As shown in Figures 1 and 2, the solar cell panel 10 comprises a support sheet 20 and a plurality of solar cell modules 30. In this disclosure, a solar cell panel 10 is formed by combining a plurality of solar cell modules 30 to form a panel. The solar cell panel 10 is constructed by attaching a plurality of solar cell modules 30 to the surface of the support sheet 20. The solar cell panel 10 extends in the x-axis and y-axis directions and has a bent shape that alternately repeats mountain folds and valley folds in the z-axis direction. Details of the bent shape will be described later. As shown in Figure 2, the solar cell panel 10 is used mounted on the upper surface of the vehicle roof R, which is approximately in the xy plane.

[0012] <Support Sheet 20> As shown in Figures 1 and 2, the support sheet 20 has a shape that is bent in a manner that alternately repeats mountain folds and valley folds, thereby forming the overall shape of the solar cell panel 10. More specifically, the support sheet 20 has equally spaced mountain fold or valley fold lines for performing the so-called Miura fold. The support sheet 20 maintains and fixes its shape in a state between being completely folded by the Miura fold and being unfolded and flat. Multiple regions A enclosed by the fold lines of the support sheet 20 are arranged in a grid pattern and each has the same rhombus shape. As shown in Figure 2, the angle a between adjacent regions A is 120°, and adjacent regions A do not lie on the same plane. Also, the angle b at which multiple regions A are inclined in the z-axis direction with respect to the xy plane, i.e., the vehicle roof R, is 30°, and none of the multiple regions A lie on the xy plane.

[0013] <Solar cell module 30> As shown in Figures 1 and 2, each solar cell module 30 has a rhombic shape similar to the rhombic shape of region A, and slightly smaller than region A. Each solar cell module 30 is mounted in a grid pattern along the rhombic shape of each region A, thereby forming the surface of the solar cell panel 10. As a result, the solar cell panel 10 has a bent shape in which mountain folds and valley folds alternately occur between adjacent solar cell modules 30.

[0014] A2. Electrical connections in the solar panel 10: Figure 3 is an explanatory diagram illustrating the electrical connections of the solar cell panel 10 in this embodiment. For the sake of explanation, the solar cell panel 10 shown in Figure 3 differs in part from the actual structure in that it lies on the xy plane and is not tilted in the z-axis direction. Also, in Figure 3, the support sheet 20 and some solar cell modules 30 are omitted from the depiction.

[0015] Each solar cell module 30 has a so-called integrated structure composed of multiple solar cells C. The number of solar cells C in each solar cell module 30 is not particularly limited, but in this embodiment, each solar cell module 30 has 15 solar cells C1 to C15. Note that C1 to C15 are collectively referred to as "solar cell C," or any single solar cell is referred to as "solar cell C." Solar cells C1 to C15 are electrically connected in series. Solar cells C1 to C15 have an elongated, strip-shaped parallelogram in the y-axis direction. The rhombus shape in each solar cell module 30 is formed by arranging solar cells C1 to C15 in the x-axis direction.

[0016] Solar cell C is constructed as a solar cell capable of generating electricity using a material having a perovskite structure. Because solar cell C is strong and flexible against bending, it is possible to arrange many elongated strip-shaped solar cell Cs on each solar cell module 30. Solar cell C is fabricated, for example, by laser patterning.

[0017] Multiple solar cell modules 30 are electrically connected to multiple positive electrodes PE, multiple negative electrodes NE, a positive busbar PB, and a negative busbar NB. Multiple solar cell modules 30 arranged in the y-axis direction are electrically connected in parallel to the same positive electrode PE and the same negative electrode NE extending in the y-axis direction. More specifically, each solar cell C1 in each solar cell module 30 is electrically connected to the positive electrode PE. Similarly, each solar cell C15 in each solar cell module is electrically connected to the negative electrode NE. In addition, each positive electrode PE arranged in the x-axis direction is electrically connected to the positive busbar PB. Similarly, each negative electrode NE arranged in the x-axis direction is electrically connected to the negative busbar NB. Thus, multiple solar cell modules 30 are electrically connected in parallel to one another. The positive busbar PB and negative busbar NB are electrically connected to the vehicle battery and electrical equipment mounted in the vehicle.

[0018] As described above, since the plurality of solar cell modules 30 are electrically connected in parallel to each other, even if the current value decreases in one solar cell module 30 due to reasons such as a solar cell module 30 with low illuminance due to sunlight or a failed solar cell module 30, it is possible to suppress a decrease in the current value of the entire solar cell panel 10. Therefore, it is possible to suppress a decrease in the power generation amount of the solar cell panel 10.

[0019] When the plurality of solar cell modules 30 are electrically connected in parallel to each other, if the voltage value decreases in one solar cell module 30, there is a risk that the voltage value of the entire solar cell panel 10 will decrease. However, since each solar cell module 30 has a plurality of strip-shaped solar cells C1 to C15 that are electrically connected in series, the total voltage value of the plurality of solar cells C can be set as the output voltage of each solar cell module, and the output voltage of each solar cell module can be increased. Therefore, the electric power generated by the solar cell panel 10 can be appropriately supplied to the vehicle battery or the electrical equipment mounted on the vehicle.

[0020] A3. Evaluation of increase in power generation amount: Next, the degree to which the power generation amount of the solar cell panel 10 in the present embodiment increases is calculated under several assumptions, as compared with a configuration in which the solar cell panel 10 is flatly arranged on the vehicle roof R (hereinafter referred to as "comparative example"). Generally, since the average irradiation angle of sunlight in Japan (the angle when the direction perpendicular to the ground is 0°) is 30°, in this calculation, it is assumed that sunlight reaches the ground at an irradiation angle of 30°. Also, the power generation amount when the relative irradiation angle of sunlight with respect to each solar cell module 30 (the angle when the direction perpendicular to the solar cell module 30 is 0°) is 0° is set to 100. In the case of the comparative example, since sunlight irradiates each solar cell module 30 at a relative irradiation angle of 30°, the power generation amount of the comparative example is expressed by the formula 100 × cos 30° and calculated as "86.6".

[0021] The solar cell panel 10 in this embodiment includes a plurality of solar cell modules 30 inclined at an angle of 30° in the z-axis direction with respect to the vehicle roof R. Therefore, in this calculation, it is assumed that the solar cell modules 30 with a smaller relative irradiation angle of sunlight to the solar cell module 30 and the solar cell modules 30 with a larger relative irradiation angle exist in the same proportion. Then, the power generation amount of the solar cell module 30 with a smaller relative irradiation angle of sunlight is expressed by the formula 100×cos(30° - 30°) and is calculated as "100". On the other hand, the power generation amount of the solar cell module 30 with a larger relative irradiation angle of sunlight is expressed by the formula 100×cos(30° + 30°) and is calculated as "50". Therefore, when not considering the expansion of the installation area of the solar cell panel 10, the power generation amount is calculated as "75" from the average value of these two numerical values.

[0022] Next, calculate the power generation amount when considering the expansion of the installation area of the solar cell panel 10. Since the ratio of the installation area of the solar cell panel 10 to the comparative example is expressed by the formula ((1 / cos30°)^2)×100(%), it is calculated as 133(%). Therefore, the power generation amount when considering the expansion of the installation area of the solar cell panel 10 is expressed by the formula 75×133(%) and is calculated as "100". That is, the power generation amount "100" of the solar cell panel 10 in this embodiment exceeds the power generation amount "86.6" of the comparative example. Thus, by expanding the mounting area of the solar cell panel 10 on the vehicle roof R, the power generation amount of the solar cell panel 10 can be increased compared to the comparative example. The above-mentioned power generation amount was calculated assuming that the irradiation angle of sunlight is 30°. However, the smaller the irradiation angle of sunlight, that is, the closer the country is to the equator than Japan, the greater the increase rate of the power generation amount of the solar cell panel 10.

[0023] As described above, the solar cell panel 10 has a shape in which adjacent solar cell modules 30 are bent in alternating mountain and valley folds. Compared to a configuration in which the solar cell panel 10 is laid flat on the vehicle's mounting surface, the mounting area of ​​the solar cell panel 10 can be increased. Therefore, the amount of power generated by the solar cell panel 10 can be increased.

[0024] Furthermore, since the multiple solar cell modules 30 are electrically connected in parallel to each other, even if the current value in one solar cell module 30 is low, a decrease in the overall current value of the solar panel 10 can be suppressed. Therefore, a decrease in the amount of power generated by the solar panel 10 can be suppressed.

[0025] Furthermore, since each solar cell module 30 has multiple strip-shaped solar cells C electrically connected in series, the sum of the voltages in the multiple solar cells C can be used as the output voltage of each solar cell module 30, thereby increasing the output voltage of each solar cell module 30. As a result, the power generated by the solar panel 10 can be appropriately supplied to various devices.

[0026] B. Other Embodiments (B1) In this embodiment, the solar cell panel 10 is mounted on the upper surface of the vehicle roof R. In this respect, compared to a configuration in which the solar cell panel 10 is arranged flat with respect to the vehicle roof R, the solar cell panel 10 in this embodiment may be at increased risk of failure due to air resistance when the vehicle is in motion. Therefore, a transparent sheet may be provided on the top of the solar cell panel 10 to reduce air resistance when the vehicle is in motion. Alternatively, the strength of the solar cell panel 10 may be improved by filling the valley-fold portions of the solar cell panel 10 with a transparent resin.

[0027] Furthermore, rainwater may accumulate in the valleys of the solar panel 10, potentially causing the solar panel 10 to malfunction. Therefore, the solar panel 10 may be configured with openings on a part of its surface to allow rainwater to be properly drained to the outside. In this case, to ensure that rainwater is properly drained from the openings even in the presence of surface tension, a coating to reduce surface tension may be applied around the openings. Alternatively, instead of applying a coating, the top of the solar panel 10 may be covered with a flat, transparent shielding material. Note that the solar panel 10 is not limited to the top surface of the vehicle roof R, but may also be mounted on other locations such as the top surface of the vehicle's hood or the side of the doors.

[0028] (B2) In this embodiment, the support sheet 20 was provided with mountain folds or valley folds for performing a Miura fold, but the disclosure is not limited thereto. The support sheet 20 may be provided with folds formed by various folding methods, such as folding it in half or in thirds after an accordion fold. Furthermore, the support sheet 20 only needs to be continuous in at least one arrangement direction and have a shape that is bent in such a way that mountain folds and valley folds are alternately repeated, for example, a part of the support sheet 20 may extend on the xy plane.

[0029] (B3) In this embodiment, the solar cell panel 10 has a support sheet 20, but this disclosure may omit it. The solar cell panel 10 may also be configured such that the solar cell modules 30 are directly connected to each other by means of an adhesive or the like.

[0030] (B4) In this embodiment, the solar cell C was configured as a solar cell capable of generating electricity using a material having a perovskite structure, but the disclosure is not limited thereto. The material constituting the solar cell C may be composed of crystalline silicon, amorphous silicon, CIS-based, CIGS-based, CdTe-based, organic thin-film-based, or dye-sensitized materials.

[0031] (B5) In this embodiment, the angle a between adjacent regions A in the support sheet 20 is 120°, and the angle b in which region A is inclined in the z-axis direction with respect to the vehicle roof R is 30°, but the disclosure is not limited thereto. Angle a can be any angle between 90° and less than 180°, and angle b can be any angle between 1° and 45°. The values ​​of angle a and angle b may differ for each region A. In addition, the values ​​of angles a and b may be appropriately set according to the area of ​​use and latitude of the solar cell panel 10, i.e., the angle of sunlight irradiation.

[0032] This disclosure is not limited to the embodiments described above, and can be implemented in various configurations without departing from its spirit. For example, the technical features in the embodiments corresponding to the technical features in each form described in the summary of the invention can be replaced or combined as appropriate in order to solve some or all of the above-described problems, or to achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate. [Explanation of symbols]

[0033] 10…Solar panel, 20…Support sheet, 30…Solar module, A…Area, C(C1~C15)…Solar cell, NB…Negative busbar wire, NE…Negative electrode, PB…Positive busbar wire, PE…Positive electrode, R…Vehicle roof

Claims

[Claim 1] A solar panel for use in vehicles, The solar panel comprises a plurality of solar cell modules arranged in a grid pattern that constitute the surface of the solar panel, The solar cell panel has a shape in which, in at least one continuous solar cell module in the array direction, adjacent solar cell modules are bent in a manner that alternately repeats mountain folds and valley folds. Each of the solar cell modules has multiple strip-shaped solar cells that are electrically connected in series, The aforementioned plurality of solar cell modules are electrically connected in parallel to one another, forming a solar panel.

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